<template>
  <view>
    <!-- 搜索栏 -->
    <!-- 还未封装click事件 -->
    <my-search @click="gotoSearch"></my-search>
    <!-- 渲染分类页面的基本结构 -->
    <!-- scroll-view实现滑动区域 -->
    <view class="scroll-view-container">
      <!-- 左侧 -->
      <scroll-view class="left-scroll-view" scroll-y="true" :style="{height: wh + 'px'}">
        <block v-for="(item,i) in catelist" :key="i">
          <!-- 如若i等于active的值，给予active类名，否则就不给其它类名 -->
          <view :class="['left-scroll-view-item', i === active ? 'active' : '']" @click="activeChanged(i)">
            <!-- 绑定点击事件，点击激活项的索引 -->
            {{item.cat_name}}
          </view>
        </block>
      </scroll-view>
      <!-- 右侧 -->
      <scroll-view class="right-scroll-view" scroll-y="true" :style="{height: wh + 'px'}" :scroll-top="scrolltop">
        <view class="cate-lv2" v-for="(item2,i2) in catelevel2" :key="i2">
          <view class="cate-lv2-title">
            / {{item2.cat_name}} /
          </view>
          <!-- 三级分类的数据列表 -->
          <view class="cate-lv3-list">
            <!-- 三级分类item项 -->
            <view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
              <!-- 三级分类的图片与文本 -->
              <image :src="item3.cat_icon"></image>
              <text>{{item3.cat_name}}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<script>
  // 导入自己封装的 mixin 模块
  import badgeMix from '@/mixins/tabbar-badge.js'
  export default {
    // 将 badgeMix 混入到当前的页面中进行使用
    mixins: [badgeMix],
    data() {
      return {
        //当前设备可用高度
        wh: 0,
        catelist: [],
        //默认激活项
        active: 0,
        //二级分类列表
        catelevel2: [],
        //滚动条距离顶部距离
        scrolltop: 0
      };
    },
    onLoad() {
      // 调用uni.getSystemInfoSync的API,获得数据
      const sysInfo = uni.getSystemInfoSync()
      this.wh = sysInfo.windowHeight - 50
      this.getCateList()
      this.getCateLevel2()
    },
    methods: {
      async getCateList() {
        // 发起请求
        const {
          data: res
        } = await uni.$http.get('/api/public/v1/categories')
        // 判断是否获取失败
        if (res.meta.status !== 200) return uni.$showMsg()
        // 转存数据
        this.catelist = res.message
        this.catelevel2 = res.message[0].children
      },
      activeChanged(i) {
        this.active = i
        //监听一级事件切换，重新为二级分类赋值
        this.catelevel2 = this.catelist[i].children
        //重新赋值scrolltop
        this.scrolltop = this.scrolltop === 0 ? 1 : 0
      },
      async getCateLevel2() {

      },
      gotoGoodsList(item3) {
        uni.navigateTo({
          url: '/subpkg/goods_list/goods_list?cid=' + item3.cat_id
        })
      },
      gotoSearch() {
        uni.navigateTo({
          url: '/subpkg/search/search'
        })
      }
    }
  }
</script>

<style lang="scss">
  .scroll-view-container {
    display: flex;

    // px(宽高固定)
    .left-scroll-view {
      width: 120px;

      .left-scroll-view-item {
        background-color: #F7F7F7;
        line-height: 60px;
        text-align: center;
        font-size: 12px;

        // 即包含.left-scroll-view-item又包含active使用的特定样式
        // 使用伪元素
        &.active {
          background-color: #FFFFFF;
          position: relative;

          &::before {
            content: '';
            display: block;
            width: 3px;
            height: 30px;
            background-color: #C00000;
            position: absolute;
            top: 50%;
            left: 0;
            transform: translateY(-50%);
          }
        }
      }
    }
  }

  .cate-lv2-title {
    font-size: 12px;
    font-weight: bold;
    text-align: center;
    padding: 15px 0;
  }

  .cate-lv3-list {
    display: flex;
    flex-wrap: wrap;

    .cate-lv3-item {
      width: 33.33%;
      margin-bottom: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;

      image {
        width: 60px;
        height: 60px;
      }

      text {
        font-size: 12px;
      }
    }
  }
</style>